Epicyclic change-speed gear



Feb. 28, 1928. E. PosTEL EPIcYcLIc CHANGE sPEED'Gl-:AR

Filed Nov. 25. 1927 Jr p m4 7 www..

Patel-lad Feb.I 2s, 1652s.

UNITED STATES Y y 1,666,356 PATENT QFFICE.

EMIL IOSTEL, OF LUDWIGSHAFEN#ON-THE-RHIN, GERMAN-Y'.

ErrcYcLIc GRANGE-SPEED GEAR.

y Application med November 25, 1927, serial N6. 235,644-, ana in Germany catcher 1, 1925.

The present invention consists in an epicyclic change speed gear 1n which bythe employment of rotating crank and guide what similar manner as in' the present inven-' tion, two or more associated sets of planet wheels arranged upon a common shaft. In these known constructions however, the num ber of attainable ratios is always limited, moreover, considerable wear and unpleasant 1 noise are caused by. the sudden throwing in and out of the particular ratios "of transmission. l

The object of the present invention is to provide a gear free from these drawbacks which enables any desired ratio-of transmission lying between zero and a maximum to be obtained Pby a gradual change. Another object of the invention is to provide a gear of this kind in which all the elements of the gear remain permanently in engagement and in which changes in the ratio of transmission may be effected rapidly and yet without any shock or noise. The improved gear has a very high degree of eliiciency and is therefore suitable for motor cars. f

These objects are according to.` the invention attained by connecting the planet wheels of two rotating planet vwheel sets, by means of rotating crank and guide motions usually known under the name of Whitworths gears. The axes of the shafts of the guides and the cranks are adapted to be moved relatively to each other in the periph- -eral direction for the purpose 0f changing the ratio of transmission. The crank shafts associated with the first set of planet wheels rotate with uniform speed, whilst the correspending guide shafts .of the second set of planet wheels are driven with a non-uniform speed through the said crank and guide motions. The retardations of speed occurring during each revolution of the guide shafts, are transmitted by the aid of free wheel clutches upon the corresponding planet wheels. The ear wheels employed may be single or mu tiple helical gears so that' all the advantages resulting from the employment of helical gearing may be real- 1ze The accompanying drawings show by way of example one construction embodying the features of the invention.

Fig. 1 is a sectionalV elevation on line a-b of Fig. 2 showin a gearing having twelve planet wheels an six crank and guide motions.-

Fig. 2 is a section on line c-d of Fig." 1. 1 designates a casing which is rotated with uniform speed and carries upon pivots 2 fixedly mounted in said casing, planet wheels 4, each of which is provided with a crank pin 3. The axes of the crank discs ,are as may be seen from Fig. 1 parallel to each other. The planet wheels 4 roll upon a stationary sun wheel 5. The crank pins 3 are provided with crank blocks 6 which engage vgrooves ofthe crank guides 7. The crank guides are rotatably mounted in a second casing 8 which is fixed to the casing 1 to rotate therewith, but

is capable of angular adjustment', relatively to the casing 1, both casings being mounted upon a common shaft 9. Any suitablemeans for instance a hand lever, may be employed for adjusting the casing 8 relativeliy to the casing 1.- The shafts 13 of the cran guides 7 carry free wheel clutches 10 upon which are rotatably mounted planet wheels 11. The latter wheels roll upon a sun wheel 12 vlhi'fcth isadaptedto rotate freely upon the s a 9.

The operation of the gear is as -followszu f e Upon the casings 1 and 8 being adjusted for instance by means of a hand lever, in such a manner as to cause the axis of thecrank guide shaft 13 to coincide with the 'axis of the corresponding crank shaft 2,

during uniform rotation of the casings 1 and 8 the planet wheels 4 will roll upon the'.

the corresponding crank shaft 2, the rotary movement being as is well known, of a nonf' `uniform kind, part of the rotation of the shaft 13taking place with an accelerated producing the driving action.' It should .planet wheel in question durin and the. other part with a retarded speed. A planet wheel .11 whose shaft turns with a retarded speed, cannot maintain its uniform speed of rotation as it is incapable of over'- running the shaft 11 upon which it is mounted. The planet wheel 11 being connected to its shaft by afree Wheelx clutch is therefore compelled to assume the same retarded speed of rotation. The4 result is that the sun wheel l2 which has hitherto been stationary, will be carried in the direction of rotation of the casings land 8 by the a period corresponding to the rolling o one-sixth of the periphery of the planet wheel upon c the sun wheel. This period corresponds to the maximum retardation of the planet wheel .11 relatively to its corresponding planet wheel 4. The same-operation is repeated successively in connection with each following planet wheel, so that whilst any of the six planet wheels 11 transmits the drive u on the sun wheel 12, the remaining planet w eels 11 revolve freely upon theirl shafts without transmitting movement. It will thus be seen that the planet'wheels 11 drive asun Wheel one after the other and thus impart to the wheel 12 uniform rotation in one direction, the speed of which .depends upon the eccentricity 'e of the shafts 2 and 13 produced by the shifting of the casing 8 with regard to .the casing 1. The ratio of transmission may thereforel be gradually changed from zero to a maximum.

The gear nia :be adapted for reversin the 'direction o rotation ofthe sun 'whee 12, by 'employin planet wheels 11 of a larger diameter t an that of the wheels 4. In the' above described gear the driving action of the crank guide rshafts 13 is due to the retardation of saidshafts, it will there-v fore be understood that instead' of the retardation of the shafts the acceleration of the shafts could equally well Abe employed for also be borne in mind thatin that case the Lacasse diameter of the planet. wheels 11 must be chosen smaller than that of the wheels 4 for the purpose of reversing the direction of rotation.

I claimv p p 1. An epicyclic change speed gear comprising in combination: a stationary sun wheel; a set of planet wheels associated therewith; a casing carrying said set of planet wheels; a second sun wheelV capable of rotation; a set of planet wheels associated with said secondsun wheel; a casing carrying said second .set of planet wheels; and means for transmitting rotation from the planet Wheels of the first set 'to the planet wheels of the second set, said means comprising crank guide motions ofadjustable eccentricity and free wheel clutches.

2. An epicyclic 'change speed gear comprising in combination: a stationary sun wheel; a set fof planet Wheelsassociated therewith; a casing carryingvsaid set of planet wheels; a second sun wheel capable of rotation; a set of planet wheels associatedl with said second sun wheel; a casing carrying said second set of planet Wheels; and means interposed between corresponding planet wheels of the said two' sets for transmltting non-uniformly rot-ation of'4 the f wheels of the first set -to the wheels of the secondset in one direction only.

3. An epicyclic change spleed gear comprising in combination: a s aft; a station-v ary su'n wheel; a'second sun wheel rotatable on said shaft; a casing mounted on said shaft to rotate therewith; 'a set of planet wheels associated with the said stationary sun wheel"v and carried `b saidV casing; a

Second set of planet whee associated-with' -the second sun wheel and carried by said lcasing; crank and`s1ot motions for nonuniform `transmission of'rotation fromA the lplanet wheelsof one set to the planet wheels of the otherset; free wheel clutches interposed between the said crank andl slotv motions and the planet wheels of one set; and means for adjusting the eccentricity ofthe said crank and slot motions by angular displacement of one set of planet wheels rela.- tively to the other set.

Signed ,at Frankfort-on-the-Main, Germany, this 10th day of November,'1927.

EMIL Pos'rEL.

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